The present invention relates generally to medical devices and methods, and more particularly to catheter devices and methods that are useable to form channels (e.g., penetration tracts) between vessels such as arteries and veins and vessels and other anatomical structures, in furtherance of a therapeutic purpose such as bypassing an arterial blockage, delivering therapeutic agents, creating an A-V dialysis fistula or performing other interventional procedures.
Atherosclerotic cardiovascular disease remains a major cause of premature death and morbidity, in most regions of the world. Various transluminal, catheter-based interventional techniques have been used, or proposed for use, to dilate or otherwise treat atherosclerotic obstructions that occur in coronary and/or peripheral arteries. These therapies have traditionally focused on treating the disease intraluminally, or from xe2x80x9cwithinxe2x80x9d the vessel lumen.
The devices, systems and methods proposed in previous disclosures from which the present application claims priority introduce a new method of percutaneous revascularization wherein the cardiac veins may either be arterialized, or may be simply used as bypass grafts. Various percutaneous, transluminal techniques have thus been developed for bypassing obstructions in coronary or peripheral arteries through the use of the adjacent vein(s) as in situ bypass conduit(s); (e.g. using catheters to perform extra luminal procedures outside the diseased vessel lumen. In some instances, these procedures may be performed by a venous approach wherein a tissue penetrating catheter is inserted into a vein and the desired passageway or puncture is initially formed by facilitating the passage of a tissue penetrator (e.g., a flow of energy or an elongate penetration member) from a catheter, through the wall of the vein in which the catheter is positioned, and into a target location such as the lumen of an adjacent vessel (e.g. the artery). Alternatively, some of these procedures may be performed by an arterial approach wherein the catheter is inserted into an artery and the desired passageway or puncture is initially formed by facilitating the passage of a tissue penetrator (e.g., a flow of energy or elongate penetration member) from the catheter, through the wall of the artery in which the catheter is positioned, and into the target location such as the lumen of an adjacent vessel (e.g. a vein).
The present invention derives from and expands upon the previous disclosures with respect to stabilizing a tissue penetration catheter in a body lumen.
The prior art has included tissue penetrating catheters for uses other than those claimed in this patent application, but such prior art tissue penetrating catheters fail to include all of the elements required for optimal use in the methods of this, invention or for precise targeting of the location at which the penetration tract is to be made. For example, U.S. Pat. No. 5,464,395 (Faxon et al.) discloses a catheter for delivering therapeutic and/or diagnostic agents to tissues surrounding a body passageway (e.g., the lumen of a blood vessel). The catheter devices disclosed by Faxon et al. generally comprise a catheter, a needle cannula that is able to be projected outboard of the catheter so as to deliver the desired agents to the tissue, and preferably one or more inflatable balloons useable to perform a balloon angioplasty procedure in addition to the injection of drugs or other therapeutic or diagnostic agents into tissues surrounding the vessel in which the catheter is positioned. However, the Faxon et al. device does not incorporate any means for precisely aiming its needle to a specific target location. Thus, while the Faxon et al. device may be useable to deliver drugs or other materials to relatively non-specific locations surrounding a vessel in which the catheter is positioned, its lack of sophisticated orientation and aiming apparatus renders it less than optimal for performing injections into specific or discrete target locations such as small anatomical structures, other blood vessels, etc.
Accordingly, there remains a need in the art for the development of new stabilized tissue penetrating catheters that can be used for revascularization, drug delivery, transluminal interstitial interventions and other procedures wherein it is desired to pass a tissue penetrator from a catheter, through the wall of a vessel (e.g, blood vessel or other body lumen) in which the catheter is positioned and to a target location (e.g., another blood vessel, a specific location within tissue, an organ, tumor or other anatomical target structure or lesion.
The tissue-penetrating catheter must be placed in proper rotational orientation within the blood vessel, prior to facilitating the passage of the tissue penetrator therefrom, to ensure that the tissue penetrator is aimed or positioned to enter the target. To facilitate such aiming of the tissue penetrator, some of the previously described tissue penetrating catheters have included a penetrator direction marker that indicates the direction in which the tissue penetrator will pass from the catheter and an imaging element (e.g., an intravascular ultrasound imaging transducer) that is useable to image the target and the penetrator direction marker. The catheter can then be rotated within the blood vessel until the penetrator direction marker is aligned with the target, thereby indicating that subsequent advancement of the tissue penetrator from the catheter will result in the formation of the desired penetration tract between the blood vessel in which the catheter is positioned and the target.
The catheter stabilizers of the present invention facilitate accurate and reliable positioning, aiming and actuation of a tissue penetrating catheter in a blood vessel so that an adjacently located blood vessel or other anatomical target can be accurately penetrated. Also, the catheter stabilizers of the present invention may serve to perform other functions as enumerated herebelow.
In accordance with the invention, there are provided tissue penetrating catheter devices that generally comprise a) an elongate catheter body, a tissue penetrator (e.g., solid or hollow needle, knife, blade, radiofrequency cutter, bipolar tissue cutter, monopolar tissue cutter, laser or other flow of tissue-penetrating energy) that is passable or advanceable from the catheter body to penetrate outwardly through the wall of a blood vessel or other tubular anatomical structure in which the catheter is positioned to a target location (e.g., another blood vessel, organ, interstitial location, tumor, etc.) and c) a stabilizer that is deployable laterally in at least one direction from the catheter body prior to and/or during passage or advancement of the penetrator to stabilize (e.g., deter some movement of) at least a portion of the catheter body within the vessel (e.g., blood vessel or other tubular anatomical structure) in which the catheter body is positioned. The stabilizer may comprise any suitable type of moveable or expandable member, such as:
a compliant balloon;
a non-compliant balloon;
an self-expanding frame formed of wire, metal or polymer mesh or other suitable material (e.g., spring steel, elastic, self expanding material, shape memory material such as a NiTi alloy) that transitions from a non-deployed configuration to a deployed configuration in response to a temperature change or passage of energy therethrough, such frame being initially restrained by a sheath, clip or other restraint means and being subsequently expandable to its deployed configuration upon removal of the restraint therefrom;
a substantially rigid member or foot that is extendable laterally from the catheter body (e.g., in a direction that is radially opposite the direction in which the tissue penetrator passes from the catheter body; or,
a portion of the catheter body itself that is adapted to curve, loop or otherwise deform when desired to thereby stabilize the position of the catheter body within the vessel.
Still further in accordance with the invention, deployment of the stabilizer may accomplish one or more of the following effects:
prevention of movement of at least a portion of the catheter body during tissue penetration;
bringing the tissue penetrating catheter body closer to the target (thereby minimizing the distance that must be traveled by the tissue penetrator;
blocking blood flow through the vessel (e.g., blood vessel or other anatomical structure) in which the catheter body is positioned;
providing hemostasis during and/or after the tissue penetration;
causing tamponade or compression of tissues or structures located adjacent the penetration tract created by the tissue penetrator;
dilating the vessel (e.g., blood vessel or other anatomical structure) in which the catheter body is positioned to facilitate advancement of the tissue penetrating catheter or for other purposes;
dilating or opening the vessel (e.g., blood vessel or other anatomical structure) with a balloon or expandable stabilizer/dilator and subsequently using the balloon or expandable stabilizer/dilator to stabilize the catheter while allowing some blood flow past or through the balloon or expandable stabilizer/dilator.
straightening the catheter body in the area of the tissue penetrator and/or any imaging element to facilitate imaging and/or aiming of the tissue penetrator at the target;
Still further in accordance with invention, the catheter stabilizer may include material that is imageable by radiographic, ultrasound or other means, such stabilizer thereby performing additional functions as a marker to facilitate longitudinal and or rotational positioning of the catheter within the vessel. In this regard, in embodiments wherein the stabilizer comprises an inflatable balloon, the balloon made be inflated with a radiographic contrast medium thereby rendering the balloon radiographically visible. In other embodiments, imageable elements such as a metal wire, foil or other material made be positioned at one or more discrete locations such as at the outer-most extent of the stabilizer when the stabilizer is fully deployed, thereby providing marker(s) that may be used to facilitate precise rotational positioning of the catheter body and aiming of the tissue penetrator at the target.
Still further in accordance with the invention, the stabilizer and/or catheter body may incorporate one or more flow-through channels to permit blood flow to pass the stabilizer when the stabilizer is deployed.
Still further in accordance with the invention, the catheter body may incorporate one or more infusion lumens with infusion ports to permit dye or other imageable material to be injected upstream of the deployed stabilizer to check for flow-through or past the stabilizer or alternatively occlusion of the vessel, in situations where it is desired for the stabilizer to effect such occlusion. In this regard, it will be noted that in some applications it may be desirable for the stabilizer to be deployed such that it expands substantially across the luminal diameter of the vessel but does not firmly coapt with the vessel wall. In such embodiments, the ability to inject radiographic contrast medium, dye or other material upstream of the stabilizer will enable the operator to determine the amount of blood flow that is being permitted to pass the stabilizer, thereby ascertaining whether the stabilizer has been deployed or extended to its desired position or whether more or less deployment or extension is necessary prior to proceeding with the procedure.